THE BASICS OF REMOTE VIDEO ACCESS Consumer Guide English Version1.0 www.lorexcctv.com Copyright © 2007 Lorex Technolog Inc. Table of Contents Introduction............................................................................................................................................................. 2 Background to the Technology............................................................................................................................... 3 Types of Surveillance Systems.......................................................................................................................... 3 What is the difference between Local and Remote Network Surveillance?...................................................... 3 How do I configure my gateway/router?............................................................................................................. 5 How to I locate the video devices?..................................................................................................................... 5 What is the difference between a Static and Dynamic IP Addresses? .............................................................. 6 What is the difference between an internal and an external IP Addresses? ..................................................... 6 What is port forwarding? ................................................................................................................................... 7 What is Domain Name Service (DNS)?............................................................................................................. 7 What does a Dynamic DNS service do?............................................................................................................ 7 Implementing Remove Access............................................................................................................................... 7 Where is the best place to start?....................................................................................................................... 7 What does setting up a gateway/router involve?................................................................................................ 8 Is Dynamic DNS really necessary?.................................................................................................................... 8 What do I need on the client side to display video?........................................................................................... 8 Glossary.................................................................................................................................................................. 8 Conclusion.............................................................................................................................................................. 9 Introduction There are many video surveillance products available today that allow the video signals to be accessed via digital, network connections. These products are suitable for use over Internet connections, allowing access from anywhere in the world. However, many users are not familiar with the technologies needed to get this to work reliably. This document provides a background to networking and remote network access concepts pertaining to video surveillance and is intended to give the Do-It-Yourself user a fundamental understanding of key concepts for all network video products. 2 Background to the Technology Types of Surveillance Systems In discussing video surveillance systems there are three types to consider; – Direct Surveillance – Local Network Surveillance – Remote Network Surveillance Direct Surveillance Systems display the video images on a monitor or PC-system screen without using a data network, as shown in the following figure. Only the cameras connected to the monitor or the PC-system can be viewed on their respective systems; PC Video System Monitor Figure 1: Direct Surveillance Systems Network Surveillance systems use a data network to connect to the video devices, so that the video signals can be accessed using a digital data protocol across the network. To do this the devices need to be designed for Internet Protocol (IP) networking. What is the difference between Local and Remote Network Surveillance? If you wish to view the video images from any of the network-enabled video devices using a viewer application or web browser that is connected to the Local Area Network(LAN), such as the PC(a) in the figure below, then this is considered local network surveillance. In this case the video signals never reach the Internet and there is no special setup required. If you wish to view the video from a network location not directly connected to the LAN you must go through the Internet. This is considered remote network surveillance and remote access configuration is required. The two figures below illustrate the differences between these. 3 PC Video System Monitor Video Server Network Switch Network Camera PC (a) Figure 2: Local Network Surveillance In the figure 2 above, the video is displayed on a computer, PC(a), that is connected to the Local Area Network. In the following figure 3, the video is being monitored by a computer PC(b) that is attached to the Internet at some remote location. Hence all connections from the remote computer needs to traverse the Internet Gateway between the Internet, or Wide Area Network (WAN) and the Local Area Network (LAN) to reach the Video device. The video signal need to traverse the gateway in the reverse direction. 4 PC Video System Monitor Video Server Gateway/Switch Network Camera PC (b) Figure 3: Remote Network Surveillance When you are viewing the video signals across the Internet, you need to consider; How do I configure my gateway/router? This question depends on the particular model of router you have. Nearly all models support some form of inbound TCP/IP routing, or port forwarding, and there are many resources to help you to forward an incoming connection to your video device, including online guides and technical support from Lorex at: (http://www.lorexcctv.com). You can also refer to www.portforward.com for details on a large variety of routers. How to I locate the video devices? The second question depends on the nature of your Internet connection. If you are fortunate to have a static IP Address, then this is all you will need. Static IP Addresses are typically available to corporations and organizations that run servers. Service providers charge substantially more for static IP addresses and will often 5 rent them in blocks. If, like most broadband Internet users, you have a service provider who assigns you a temporary IP Address and changes it from time to time, then you will need to sign up for a Dynamic DNS service. What is the difference between a Static and Dynamic IP Addresses? IP Addresses are the numbers used by the Internet Protocol(IP) to identify your computer or device. Every computer or device that wants to communicate over the Internet must have an address, unique to that computer or device. Internet Service Providers can issue IP Addresses in two ways; Static assignment: This is simply determining the address to be used and (usually manually) entering it into the computer or device. The number will not change, and may not be used by any other device. Dynamic assignment: This utilizes a protocol calls Dynamic Host Configuration Protocol (DHCP) that generates an IP Address and leases(i.e. provides) it to your computer or device for a predetermined length of time. After that time expires, your computer or device must request a new IP Address. There is usually no guarantee that the new IP Address will be the same as the old one, and in many practical instances it isn't. What is the difference between an internal and an external IP Addresses? Every device that communicates over the Internet must have a unique IP Address. These are all external, or public, IP Addresses. However, there are ranges of IP Addresses that are excluded from this address space, so that they can be used internally by devices connected via Local Area Networks. These are internal, or private, IP Addresses. If devices that are using internal addresses wish to communicate with devices on the Internet, they must pass their messages through a network gateway, which will map the internal IP Addresses into a valid external IP Address. This is called Network Address Translation (NAT), as shown in the following figure. Internet LAN IP Address in msg on the Internet from: 216.176.57.75 IP Address in msg to: 216.099.34.23 on the LAN Gateway/Router from: 192.168.1.55 Device to: 216.099.34.23 Figure 4: Example of Network Address Translation 6 What is port forwarding? Internet Protocols use IP Addresses to identify devices on the Internet, and ports to identify specific services within the devices. When a network gateway maps the messages coming from the Internet to individual internal IP Addresses(i.e. devices) on the LAN it does so on a per port basis. This is known as port forwarding. Internet LAN aps to Device A msg to m 168.1.55 216.176.57.75 192. port 8000 port 8000 Gateway/Router msg to 216.176.57.75 maps to 192 port 8001 .168.1.6 po 6 Device B rt 8001 Figure 4: Example of Port Forwarding What is Domain Name Service (DNS)? As most Internet users are aware, servers on the Internet are usually identified by their Universal Resource Locators, or URLs. These are protocol identifiers and domains and subdomains arranged in an hierarchy separated by periods ('.'), for example;